Firefox offered some compelling features, besides slightly more robustness (but slightly less zippiness) than Opera. (And both with better security than IE.) Firefox is also starting to get some nifty plug-in extensions.
Integrate ad-blocking into the browser. Right-click menu item is used to teach it which servers/URLs to block.
Well-designed mouse gesture style navigation. (It's actually a pie menu, which is even better, IMHO.) Great because it is thoroughly customizable.
Let's you drag and rearrange tabs (when you have multiple pages open in the tab bar). This should so be a part of the browser interface.
Here's a tip if, like me, you prefer every page be tabs within one application window:
Enter "about:config" in the location bar to reveal your Firefox configuration variables.
Right click on the value and toggle it to "true".
(You can close that page now.)
Open the preferences dialog box (Tools|Options...)
In the Advanced section, under Tabbed Browsing, is a new option to "Force links that open new windows to open in a... new tab in the same window". Yea!
The other interesting thing that's come out recently is the Greasemonkey plugin. This one's intersting since it allows you to do .
What's that mean? You can run scripts of your design (or from other people) on incoming pages. This allows you to modify the pages arbitrarily to suit your tastes. Scripts can be set to run based on the URL you're visiting, too, so that a script may only apply to a certain site.
Examples I've found useful:
Unembed - Put clickable/saveable links next to embedded (non-streaming) media.
DumbQuotes - Replaces "smart quotes" with standard ASCII quotes (useful when copying to editors or using odd fonts).
AutoReload - Force pages (you choose the sites) to auto-reload.
I expect to see many more interesting developments in this area...
The one thing that Firefox does NOT have which I really miss from Opera:
Tab bar stacked vertically. Opera lets you put the tab bar down the right edge of the app window. Since tabs are text labels, this is a much more efficient use of screen real estate -- I regularly browse with around 30 tabs open.
If anyone knows of a plugin or way to do this in Firefox, please let me know! Thanks. :)